In a conventional automatic storage/retrieval apparatus, two storage areas, which are formed by vertically and horizontally arranging racks serving as article storage places in the form of a matrix, are so provided that front surfaces thereof are opposed to each other with a prescribed space. A vertical column is moved along the front surfaces of the storage areas, to introduce/extract articles into/from respective racks of the storage areas by a picker vertically movably provided on the column.
In the aforementioned structure of the prior art, however, a vertically extended large column must be driven in order to move the pickers to a desired rack, whereby considerable power is required causing increased operating cost. Further, since subsequent introducing/extracting operation cannot be performed until an article is completely introduced into/extracted from a desired rack, introducing/extracting processing takes much time in an inefficient manner. Further, the column and the picker must be connected with a control device for controlling the same by control wires, and hence wiring processing in installation is troublesome.
In the aforementioned conventional automatic storage/retrieval apparatus, further, a fork lift mechanism for picking up a container from the lower side of the container or an extracting arm mechanism formed to be engageable with a fitting portion provided on the front surface of the container has been employed as a mechanism of the picker for extracting the container, for receiving the article, from the storage area onto the picker and returning the same from the picker into the storage area. However, the fork lift mechanism is disadvantageous in space since the containers must be arranged with sufficient intervals in the vertical direction, while the extracting arm mechanism is applicable only to specific containers having the fitting portion on the front surface.
An automatic storage/retrieval apparatus such as that disclosed in Japanese Utility Model Laying-Open Gazette No. 60-64912 has been proposed. In this apparatus, racks of a storage area are circulated in the horizontal direction by endless chains independently for respective rack stages while a device for elevationally transferring an article is vertically provided in the middle of the path for the horizontal circulation movement so that a desired article can be taken out from the rack into the device or put in the rack from the device when the rack of each rack stage is stopped in a position opposite to the put-in/take-out device.
In this apparatus, efficiency is improved since operation for introducing/extracting the articles can be performed independently for each rack stage, while considerable power is required at increased operating cost since the entire racks of each rack stage must be circulated simultaneously. Further, a pusher for pushing the article into the device from the rack or from the device into the rack must be provided for the respective rack stages without obstructing the circulation movement of the racks, so that the structure becomes complicated.